Fixed #28226 -- Replaced use of str.join() with concatenation.

2 files changed, 2 insertions, 2 deletions

diff --git a/django/http/multipartparser.py b/django/http/multipartparser.py
index 080f45f8ef..f66cf2772f 100644
--- a/django/http/multipartparser.py
+++ b/django/http/multipartparser.py
@@ -401,7 +401,7 @@ class LazyStream:
             return
         self._update_unget_history(len(bytes))
         self.position -= len(bytes)
-        self._leftover = b''.join([bytes, self._leftover])
+        self._leftover = bytes + self._leftover
 
     def _update_unget_history(self, num_bytes):
         """
diff --git a/django/http/response.py b/django/http/response.py
index 2495ebcc09..1083fd7dca 100644
--- a/django/http/response.py
+++ b/django/http/response.py
@@ -92,7 +92,7 @@ class HttpResponseBase:
             return val if isinstance(val, bytes) else val.encode(encoding)
 
         headers = [
-            (b': '.join([to_bytes(key, 'ascii'), to_bytes(value, 'latin-1')]))
+            (to_bytes(key, 'ascii') + b': ' + to_bytes(value, 'latin-1'))
             for key, value in self._headers.values()
         ]
         return b'\r\n'.join(headers)